View Compilation Error

0_0_27496025_32349.cpp: In function 'int main(int, char**)':
0_0_27496025_32349.cpp:5:29: error: 'scanf' was not declared in this scope
  while(scanf("%s %s",ch1,ch2)!=EOF)
                             ^
0_0_27496025_32349.cpp:5:32: error: 'EOF' was not declared in this scope
  while(scanf("%s %s",ch1,ch2)!=EOF)
                                ^
0_0_27496025_32349.cpp:7:22: error: 'strlen' was not declared in this scope
   int len1=strlen(ch1);
                      ^
0_0_27496025_32349.cpp:23:41: error: expected ':' before ';' token
    char t2=dot2+i?len2-1?'0':ch2[dot2+i];
                                         ^
0_0_27496025_32349.cpp:23:41: error: expected primary-expression before ';' token